I don't KNOW about Gen 6 and their ECU's but here's some speculation - someone correct me if this is off base.
We're not worried about closed loop operation because the oxygen sensor will monitor the situation and the ECU will compensate. It's the open loop operation that's critical. That's where the oxygen sensor is not in the loop, and the engine relies on various other sensors, e.g. throttle position, RPM, MAF (air grams per second) - calculated load, IAT, MAP/Boost, to choose fuel injector and ignition timing values in a map, which still have some dynamic learning involved but it's based on knock correction.
One of the most important sensors in open loop is the MAF - for example if you increase the diameter of the housing that the MAF sensor is in, it will dramatically change the calculation - the MAF calculates air flow past a hot wire and senses how much air is flowing based on how the air cools the sensor wire. If you increase the cross section that the air is flowing through, it moves slower and cools off the wire less, and if you decrease the cross section air will flow faster and cool off the wire more. The MAF is carefully calibrated based on air flow.
But because it's a hot wire sensor, what happens if you cool the charge air before it reaches the MAF? Well cooler air is automatically denser, and we have intake air temperature (IAT) sensors somewhere, and that is used as part of that calculation for air flow, so it should be fine.
I think the ability of the system to compensate for more restriction or less restriction is broad enough that as long as you don't change the way the IAT sensor and MAF sensor operate, it should be fine. The engine will probably run fine if there were no air filter at all, and with a somewhat clogged air filter - at a minimum the useful service life of a paper air filter under semi-dusty conditions.
